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  • Author or Editor: Rebecca L. Stepien x
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SUMMARY

Cardiorespiratory effects of the combination of acepromazine maleate (acp) and buprenorphine hydrochloride (bpn) were studied in 11 healthy, conscious dogs. Values for systemic and pulmonary artery blood pressure, cardiac output, arterial and venous pH and blood gas tensions, and invasive and noninvasive estimates of ventricular systolic function, preload, and afterload were obtained before sedation and after administration of each drug. Acepromazine maleate (0.1 mg/kg, iv) depressed cardiac function, compared with baseline values for unsedated dogs. Cardiac output decreased from a mean (± sd) value of 4.2 (± 1.5) L/min to 3.1 (± 0.8) L/min (P < 0.001), a change not attributed to heart rate. Pulmonary capillary wedge pressure decreased from 8.3 (± 4.2) mm of Hg to 6.5 (± 4.3) mm of Hg (P < 0.01), but mean right atrial pressure did not change. Left ventricular measurement of the maximal positive rate of pressure change (dP/dtmax) decreased from 2,668 (± 356)/mm of Hg/s to 2,145 (± 463) mm of Hg/s (P < 0.001), and ventricular stroke volume decreased from 43.2 (± 15.2) ml/beat to 32.3 (± 8.6) ml/beat. Noninvasive indices of left ventricular function, ventricular shortening fraction, peak aortic velocity, and aortic average acceleration were decreased after acp administration, but were not statistically different from baseline values. Mean systemic arterial blood pressure decreased from 121 ± 12 mm of Hg to 96 ± 13 mm of Hg 15 minutes after acp administration (P < 0.001). Total systemic vascular resistance was not significantly different from the baseline value. Sequential administration of cumulative doses of bpn (0.005, 0.01, and 0.1 mg/kg of body weight, iv), initiated 15 minutes after administration of acp, did not cause statistically significant depression of hemodynamic variables, except for heart rate, which decreased after bpn, and left ventricular dP/dtmax, which decreased slightly at the highest dose of bpn. Small, clinically insignificant changes in blood pH, venous bicarbonate concentration, and Paco2 were observed after administration of acp and bpn. Respiratory rate decreased from 60 ± 48 breaths/min to 24 ± 12 breaths/min, and sedation level was significantly (P < 0.05) increased from baseline values by administration of acp. Sedation level was further increased by administration of bpn at the lowest dose (P < 0.05). The combination of acp and bpn resulted in good to excellent sedation, but depressed ventricular function; however, most of the hemodynamic effects could be attributed to administration of acp and withdrawal of sympathetic activity.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of endurance training on QRS duration, QRS-wave amplitude, and QT interval.

Animals—100 sled dogs in Alaska.

Procedure—Dogs were examined in early September (before training) and late March (after training). During the interim, dogs trained by pulling a sled with a musher (mean, 20 km/d). Standard and signal-averaged ECG were obtained before and after training.

Results—Endurance training significantly increased mean QRS duration by 4.4 milliseconds for standard ECG (mean ± SEM; 62.3 ± 0.7 to 66.7 ± 0.6 milliseconds) and 4.3 milliseconds for signal-averaged ECG (51.5 ± 0.7 to 55.8 ± 0.6 milliseconds) without changing body weight. Increase in QRS duration corresponded to a calculated increase in heart weight (standard ECG, 23%; signal-averaged ECG, 27%). Signal-averaged QRS duration was correlated with echocardiographically determined left ventricular diastolic diameter for the X orthogonal lead (r = +0.41), Y orthogonal lead (r = +0.33), and vector (r = +0.35). Training also increased QT interval (234 ± 2 to 249 ± 2 milliseconds) and R-wave amplitude in leads II and rV2, increased peak-to-peak voltage and S-wave amplitude in the Y orthogonal lead, and decreased Q-wave amplitude in the Y orthogonal lead.

Conclusions and Clinical Relevance—Electrocardiographic changes reflected physiologic cardiac hypertrophy in these canine athletes in response to repetitive endurance exercise. The QRS duration increases in response to endurance exercise training and, therefore, may be of use in predicting performance in endurance activities. (Am J Vet Res 2000;61:582–588)

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Objective

To determine arterial blood pressure in client-owned dogs, using direct arterial puncture, oscillometry, and Doppler ultrasonography in a clinical setting.

Design

Prospective study.

Animals

28 clinically normal client-owned dogs.

Procedure

Blood pressures of nonsedated dogs were measured simultaneously, using each of the 3 methods. Mean values obtained were compared with published mean values. Ability of noninvasive methods (Doppler ultrasonography and oscillometry) to accurately predict results of the invasive method, and relationships between blood pressure and age, body weight, and degree of patient anxiety were determined.

Results

Calculated ranges of values (mean ± 2 SD) determined by direct arterial puncture were: systolic pressure, 114 to 194 mm Hg; diastolic pressure, 66 to 102 mm Hg; and mean pressure, 85 to 129 mm Hg. Ranges determined by use of oscillometry were: systolic, 110 to 190 mm Hg; diastolic, 35 to 107 mm Hg; and mean, 78 to 138 mm Hg. Ultrasonographic and oscillometric values did not accurately predict direct values, but mean values of systolic and mean pressures were similar among methods. Relationships were not detected between age or body weight and blood pressure. Significant differences in blood pressure were not detected between anxious and nonanxious dogs.

Conclusions and Clinical Relevance

Mean values of systolic, diastolic, and mean arterial blood pressure measured in nonsedated client-owned dogs, using invasive and noninvasive methods in a clinical setting, are comparable with those determined for acclimatized, trained, or sedated dogs. However, results of noninvasive methods may not accurately reflect direct values. (J Am Vet Med Assoc 1999;215:1623–1628)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether plasma cardiac troponin I (cTnl) concentrations can be used to identify cardiac involvement in dogs with hemangiosarcoma, exclude cardiac hemangiosarcoma in dogs with noncardiac hemangiosarcoma, and identify cardiac hemangiosarcoma in dogs with pericardial effusion.

Design—Cohort study

Animals—57 dogs (18 with confirmed [5 dogs] or suspected [13] cardiac hemangiosarcoma, 14 with confirmed hemangiosarcoma involving sites other than the heart [noncardiac hemangiosarcoma], 10 with pericardial effusion not caused by hemangiosarcoma, and 15 with noncardiac nonhemangiosarcoma neoplasms).

Procedures—Plasma cTnl concentration was measured, and thoracic radiography, abdominal ultrasonography, and echocardiography were performed in each dog. The cTnl concentration was compared among groups.

Results—Median plasma cTnl concentration in dogs with cardiac hemangiosarcoma was significantly higher than the concentration in each of the other groups. A plasma cTnl concentration > 0.25 ng/mL could be used to identify cardiac involvement in dogs with hemangiosarcoma at any site (sensitivity, 78%; specificity, 71 %). A plasma cTnl concentration > 0.25 ng/mL could be used to identify cardiac hemangiosarcoma in dogs with pericardia effusion (sensitivity, 81%; specificity, 100%).

Conclusions and Clinical Relevance—The median plasma cTnl concentration was higher in dogs with cardiac hemangiosarcoma, compared with the median concentration in dogs with hemangiosarcoma at other sites, dogs with other neoplasms, and dogs with pericardial effusion not caused by hemangiosarcoma. The plasma cTnl concentration may be used to identify cardiac involvement in dogs with hemangiosarcoma and to identify cardiac hemangiosarcoma in dogs with pericardial effusion. (J Am Vet Med Assoc 2010;237:806–811)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To characterize ocular findings in hypertensive dogs, determine prevalence of hypertension in dogs with ocular disease suggestive of hypertension, and examine possible relationships between degree of hypertension and ocular disease.

Design—Retrospective case series.

Animals—65 dogs initially referred for blood pressure measurement (n = 22), ophthalmic examination (25), or both (18).

Procedures—Medical records were reviewed to identify dogs examined at the teaching hospital that underwent a complete ophthalmic examination and blood pressure measurement within a 24-hour period between January 1, 2005, and December 31, 2007. Signalment, history, blood pressure measurements, ophthalmic examination findings, and any vasoactive drug treatments were recorded. Ocular lesions considered likely to be associated with systemic hypertension included retinal hemorrhage, retinal detachment, hyphema, tortuous vessels, and subretinal edema.

Results—Of the 65 dogs, 42 were hypertensive (systolic blood pressure ≥ 160 mm Hg) and 23 were normotensive. Sixty-two percent (26/42) of hypertensive dogs had ≥ 1 type of ocular lesion identified. Retinal hemorrhage was the most common ocular lesion in hypertensive dogs (17/42 [40%]). The presence of ≥ 1 type of ocular lesion had moderate sensitivity and specificity of 62% and 61 %, respectively, for identification of hypertension. Fifteen of the 25 (60%) dogs referred for blood pressure measurement after initial ophthalmic examination were found to be hypertensive.

Conclusions and Clinical Relevance—Ocular lesions are common in dogs with systemic hypertension. Dogs with hypertension or diseases associated with hypertension should be monitored carefully for evidence of ocular target organ damage, and hypertension should be systematically ruled out in dogs with characteristic ocular lesions.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To investigate the usefulness of radiographic measures of the left atrium and ventricle as surrogates for echocardiographic criteria in identifying dogs with stage B2 preclinical myxomatous mitral valve disease (MMVD).

ANIMALS

56 client-owned dogs with preclinical mitral regurgitation attributed to MMVD examined between April 19, 2016, and November 22, 2017.

PROCEDURES

Medical records were retrospectively searched, and data collected included age, body weight, heart murmur grade, and echocardiographic and radiographic measurements. Dogs were grouped according to whether they did (case dogs) or did not (control dogs) meet echocardiographic criteria used to identify dogs with stage B2 MMVD. Measurements for lateral thoracic radiographic variables normalized to vertebral body units (VBUs) were obtained, and results were analyzed to identify variables that could best discriminate between case and control dogs.

RESULTS

Three radiographic variables of left atrial size (vertebral left atrial size [VLAS], left atrial width, and the combined variable of VLAS + left atrial width) most accurately distinguished control dogs from case dogs, and the VLAS was the simplest and fastest to perform in a clinical setting. The optimal cutoff for VLAS was 2.5 VBUs (sensitivity, 70%; specificity, 84%; and likelihood ratio, 4.38), with VLAS ≥ 2.5 VBUs for case dogs. The maximum specificity cutoff for VLAS was 3.0 VBUs (sensitivity, 40%; specificity, 96%; and likelihood ratio, 10.0), with VLAS ≥ 3.0 VBUs for case dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that when echocardiography is unavailable, radiographic VLAS ≥ 3 VBUs could be used with minimal risk of false-positive diagnosis of stage B2 MMVD in dogs.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association